Hardness Conversion

Hardness Conversion Chart

Below are approximate equivalent hardness numbers for carbon and alloy steels.

Chart courtesy of the Collaboration for NDT/NDE Education led by the Center for NDE at Iowa State University.

RockwellRockwellRockwellRockwellRockwell SuperficialRockwell SuperficialRockwell SuperficialBrinellVickersKnoopSleroscopeApprox. Tensile Strength of Steel (PSI)
A Scale 60kg Diam. BraleB Scale 100kg 1/16″ BallC Scale 150kg Diam. BraleD Scale 100kg Diam. Brale15N Scale 15kg Diam. Brale30N Scale 30kg Diam. Brale45N Scale 45kg Diam. Brale3000kg 10mm Ball500g or Greater Load
80879792871865
92798692871787
9178859691861710
91778491851633
9076839690841556
90758389831478
8974829589821400
89738188811323
8872809587801245
87718087791160
877079948678107699
8669788577100498
85.66876.993.284.475.494092097
85.367.576.5938474.892090896
8566.476.192.983.674.290089595
84.765.975.792.783.173.688088293
84.465.375.392.582.773.186086792
84.164.774.892.382.272.284085291
83.86474.392.181.771.8745*82083790
83.463.373.891.881.17180082288
8362.573.391.580.470.278080687
82.661.872.691.279.769.4710*76078886
82.26172.19179.168.674077284
81.860.171.590.778.467.772075483
81.359.770.890.377.666.7653*70073581
81.159.270.590.177.266.2690725
80.858.870.189.876.865.768071680329,000
80.658.369.889.776.465.3670706324,000
80.357.869.489.575.964.7620*66069779
8057.36989.275.564.1611*65068778
79.856.868.78975.163.5601*64067777309,000
79.556.368.388.874.663591*63066776
79.255.767.988.574.262.4582*62065775297,000
78.955.267.588.273.661.7573*610646
78.654.7678873.261.2564*60063674
78.454.166.787.872.760.5554*59062573285,000
7853.666.287.572.159.9545*58061572
77.85365.887.271.759.3535*570604274,000
77.452.365.486.971.258.6525*56059471
7751.764.886.670.557.8517*55058370263,000
76.751.164.486.37057507*54057269
76.450.563.98669.556.2497*53056168253,000
76.149.863.585.76955.6488*52055067
75.749.162.985.468.354.7479*510539243,000
75.348.462.28567.753.9471*50052866
74.947.761.684.767.153.1460*49051765235,000
74.546.961.384.366.452.2452*48050564
74.146.160.783.965.751.3441470494
73.645.360.183.664.950.443346048262210,000
73.344.559.483.264.349.4425450471
72.843.658.882.863.548.441544045959
72.342.758.282.362.747.440543044758195,000
71.841.857.581.861.946.439742043557
71.440.856.881.461.145.338841042356
70.839.85680.860.244.137940041255
70.338.855.280.359.342.9369390400176,000
69.837.754.479.858.441.736038038950
69.236.653.679.257.440.435037037851166,000
68.735.552.878.656.439.134136036750
68.134.451.97855.437.833135035648
67.633.351.177.454.436.532234034647
6732.250.276.853.635.231333033746
66.43149.476.252.333.930332032845150,000
65.829.848.475.651.332.5294310318
65.229.247.574.950.231.128430030942141,000
64.828.547.174.649.730.4280295305
64.527.846.574.24929.527529030041
64.227.14673.848.428.7270285296133,000
63.826.445.373.447.827.926528029140
63.525.644.97347.227.126127528639129,000
63.124.844.372.646.426.225627028238
62.72443.772.145.725.2252265277
62.423.143.171.64524.324726027237122,000
6222.242.271.144.223.2243255267
61.699.521.341.770.643.422.223825026236
61.220.341.170.142.521.123324525835115,000
60.798.140.369.641.719.922824025334
235
96.721923024333105,000
225
9520922023432100,000
215
93.42002102263098,000
205
91.519020021629
19590,000
89.518119020628
185
87.11711801962683,000
175
851621701852579,0000
165
81.715216017523
155
78.71431501642271,000
145
7513314015421
135
71.21241301432063,000
125
66.711412013318
11556,000
62.3105110123
105
56.295100112
529095107
488690102
41818597